2007-06-07 04:00:00 PDT Sacramento -- The state Assembly narrowly approved legislation Wednesday night that would fine Californians who don't spay or neuter their pets, sending to the state Senate one of the most talked-about bills on one of the most emotional issues of the year.

AB1634, by Assemblyman Lloyd Levine, D-Van Nuys, is intended to reduce the state's large number of stray dogs and cats, and like virtually every legislative action centering around animals, it has stoked emotional debate. As lawmakers this year consider hot topics like health care reform and redistricting, one Republican assemblyman said Levine's bill had sparked more letters and phone calls from his constituents than any other issue.

The legislation would require pet owners to have their dogs and cats spayed or neutered or face a $500 fine for each animal. Owners of kittens and puppies would be required to get them spayed or neutered by the time they are 4 months old. Owners of guide dogs or animals registered as purebred could pay a fee to get an exemption, as could breeders.

It was approved on a 41-38 vote.

The vote came as lawmakers raced to meet a Friday deadline to pass legislation out of at least one house. Hallways in the Capitol were packed with lobbyists working for or against hundreds of bills.

Proponents of Levine's proposal argued Wednesday that the bill would reduce the number of dogs and cats that flood animal shelters and force the state's shelters to euthanize an estimated 500,000 animals per year. Opponents, mostly Republicans, said the measure was an unneeded mandate.

"This is a prime example of why this Legislature becomes a laughingstock, when we want to reach into that personal aspect of peoples' lives telling them this is how you need to handle your animals' reproductive capacity," complained Assemblyman Doug LaMalfa, R-Richvale (Butte County). "We ought to be tackling other issues."

But supporters argued that the measure was important, noting that local governments spend up to $250 million annually euthanizing unclaimed animals.

"We have all sorts of issues that that money could be better spent on than killing unwanted animals," said Assemblyman Dave Jones, D-Sacramento, during an hourlong debate in which one lawmaker held up a photo of his three dogs and another described the process most shelters use to kill unwanted animals.

"For almost half a million pets, no one loves them, no one cares about them, and they are killed," said Assemblyman Pedro Nava, D-Santa Barbara.

Levine modeled his legislation after a city ordinance in Santa Cruz, which he said reduced the number of animals in city shelters by 60 percent.

He said that ordinance produced "hysterical rhetoric" that pets, especially mutts, would be more costly or unavailable, but that in Santa Cruz, "pets are still available, and mutts are still available."

The legislation drew concern from small breeders who say they couldn't afford to pay the exemption fee for every animal, and those worried that low-income families have a difficult time affording spaying or neutering. Levine contended that there are programs providing free services throughout the state.

He also noted that the bill would allow pet owners who face the fine to spay or neuter their pet and avoid paying the penalty.

Levine said on the Assembly floor that he planned to amend the bill to allow families with a mutt who want to allow their pet to reproduce to get an exemption allowing for one litter.